[just_a_quack]

There has been research into common factors on the biomedical front. For example, the shank3 gene has been implicated in both ASD and Schizophrenia. https://pubmed.ncbi.nlm.nih.gov/28371232/

I'm not qualified to say whether or not these implicated commonalities affect this p-factor. It seems likely to me that disorders that affect identity, language, affect, etc. would have common features that could be passed down genetically.